1. Technical Field
The present disclosure relates to a process for causing an aspect ratio for printing to match an aspect ratio of image data.
2. Description of the Related Art
Typical image forming apparatuses allow printing to be performed without converting an image data file of a Tagged Image File Format (TIFF) format or a Joint Photographic Experts Group (JPEG) format into Page Description Language (PDL) data or the like.
An example image forming apparatus analyzes a header part of image data to identify the numbers of dots (pixel counts) in a width direction and a height direction of an image and changes the pixel counts of the image data according to the size of print sheet.
Further, some image forming apparatuses calculate the maximum size of the image at a time of printing from the total pixel count of a digital camera, an aspect ratio, and a print resolution.
According to the above-mentioned image forming apparatuses, if a width-directional resolution and a height-directional resolution of the image data are the same, an aspect ratio of a printed image is the same as the aspect ratio of the image data. In contrast, if the width-directional resolution and the height-directional resolution of the image data are not the same, the aspect ratio of the printed image is different from the aspect ratio of the image data, and hence, the printed image becomes distorted in the width direction or the height direction.
For example, as illustrated in FIG. 5, in a case where both the resolutions of the image data in the width direction and the height direction are 200 dpi, if a width-directional pixel count of the image data is 1,200 and a height-directional pixel count thereof is 800, the width of the image is 6 inches and the height of the image is 4 inches. Therefore, the aspect ratio of the image is 3:2. In a case where the image is enlarged by a magnification factor m, the width of the image is 6×m inches and the height of the image is 4×m inches. Again, the aspect ratio of the image remains 3:2. If the enlarged image data is printed at a resolution of 600 dpi, a width size of the printed image is 2×m inches (=1,200×m/600 dpi), and a height size of the printed image is (4/3)×m inches (=800×m/600 dpi). Yet again, the aspect ratio of the printed image remains 3:2.
On the other hand, as illustrated in FIG. 5, consider a case where the width-directional resolution of the image data is 200 dpi and the height-directional resolution of the image data is 100 dpi. If the width-directional pixel count of the image data is 1,200 and the height-directional pixel count thereof is 400, the width of the image is 6 inches and the height of the image is 4 inches. Therefore, the aspect ratio of the image is 3:2. When the image is enlarged by a magnification m, the width of the image is 6×m inches and the height of the image is 4×m inches. Again, the aspect ratio of the image remains 3:2. However, if the enlarged image data is printed at a resolution of 600 dpi, the width size of the printed image is 2×m inches (=1,200×m/600 dpi) and the height size of the printed image is (2/3)×m inches (=400×m/600 dpi). Therefore, the aspect ratio of the printed image becomes 3:1, which is different from the aspect ratio of the image data, and the printed image becomes distorted as illustrated in the lower right-hand portion of FIG. 5.